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Delta Between Two Patch Sets: src/pkg/net/tcpsock_posix.go

Issue 6849045: code review 6849045: net, cmd/fix: add IPv6 scoped addressing zone to INET, ... (Closed)
Left Patch Set: diff -r fc4e67d82024 https://code.google.com/p/go Created 12 years, 1 month ago
Right Patch Set: diff -r c200281fac50 https://code.google.com/p/go Created 12 years, 1 month ago
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LEFTRIGHT
1 // Copyright 2009 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4
5 // +build darwin freebsd linux netbsd openbsd windows
6
7 // TCP sockets
8
9 package net
10
11 import (
12 "io"
13 "os"
14 "syscall"
15 "time"
16 )
17
18 // BUG(rsc): On OpenBSD, listening on the "tcp" network does not listen for
19 // both IPv4 and IPv6 connections. This is due to the fact that IPv4 traffic
20 // will not be routed to an IPv6 socket - two separate sockets are required
21 // if both AFs are to be supported. See inet6(4) on OpenBSD for details.
22
23 func sockaddrToTCP(sa syscall.Sockaddr) Addr { 1 func sockaddrToTCP(sa syscall.Sockaddr) Addr {
24 switch sa := sa.(type) { 2 switch sa := sa.(type) {
25 case *syscall.SockaddrInet4: 3 case *syscall.SockaddrInet4:
26 » » return &TCPAddr{IP: sa.Addr[0:], Port: sa.Port} 4 » » return &TCPAddr{sa.Addr[0:], sa.Port}
27 case *syscall.SockaddrInet6: 5 case *syscall.SockaddrInet6:
28 » » return &TCPAddr{IP: sa.Addr[0:], Port: sa.Port, ZoneId: zoneIdTo String(int(sa.ZoneId))} 6 » » return &TCPAddr{sa.Addr[0:], sa.Port}
29 default: 7 default:
30 if sa != nil { 8 if sa != nil {
31 // Diagnose when we will turn a non-nil sockaddr into a nil. 9 // Diagnose when we will turn a non-nil sockaddr into a nil.
32 panic("unexpected type in sockaddrToTCP")
33 }
34 }
35 return nil
36 }
37
38 func (a *TCPAddr) family() int {
39 if a == nil || len(a.IP) <= IPv4len {
40 return syscall.AF_INET
41 }
42 if a.IP.To4() != nil {
43 return syscall.AF_INET
44 }
45 return syscall.AF_INET6
46 }
47
48 func (a *TCPAddr) isWildcard() bool {
49 if a == nil || a.IP == nil {
50 return true
51 }
52 return a.IP.IsUnspecified()
53 }
54
55 func (a *TCPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
56 return ipToSockaddr(family, a.IP, a.Port, a.ZoneId)
57 }
58
59 func (a *TCPAddr) toAddr() sockaddr {
60 if a == nil { // nil *TCPAddr
61 return nil // nil interface
62 }
63 return a
64 }
65
66 // TCPConn is an implementation of the Conn interface
67 // for TCP network connections.
68 type TCPConn struct {
69 conn
70 }
71
72 func newTCPConn(fd *netFD) *TCPConn {
73 c := &TCPConn{conn{fd}}
74 c.SetNoDelay(true)
75 return c
76 }
77
78 // ReadFrom implements the io.ReaderFrom ReadFrom method.
79 func (c *TCPConn) ReadFrom(r io.Reader) (int64, error) {
80 if n, err, handled := sendFile(c.fd, r); handled {
81 return n, err
82 }
83 return genericReadFrom(c, r)
84 }
85
86 // CloseRead shuts down the reading side of the TCP connection.
87 // Most callers should just use Close.
88 func (c *TCPConn) CloseRead() error {
89 if !c.ok() {
90 return syscall.EINVAL
91 }
92 return c.fd.CloseRead()
93 }
94
95 // CloseWrite shuts down the writing side of the TCP connection.
96 // Most callers should just use Close.
97 func (c *TCPConn) CloseWrite() error {
98 if !c.ok() {
99 return syscall.EINVAL
100 }
101 return c.fd.CloseWrite()
102 }
103
104 // SetLinger sets the behavior of Close() on a connection
105 // which still has data waiting to be sent or to be acknowledged.
106 //
107 // If sec < 0 (the default), Close returns immediately and
108 // the operating system finishes sending the data in the background.
109 //
110 // If sec == 0, Close returns immediately and the operating system
111 // discards any unsent or unacknowledged data.
112 //
113 // If sec > 0, Close blocks for at most sec seconds waiting for
114 // data to be sent and acknowledged.
115 func (c *TCPConn) SetLinger(sec int) error {
116 if !c.ok() {
117 return syscall.EINVAL
118 }
119 return setLinger(c.fd, sec)
120 }
121
122 // SetKeepAlive sets whether the operating system should send
123 // keepalive messages on the connection.
124 func (c *TCPConn) SetKeepAlive(keepalive bool) error {
125 if !c.ok() {
126 return syscall.EINVAL
127 }
128 return setKeepAlive(c.fd, keepalive)
129 }
130
131 // SetNoDelay controls whether the operating system should delay
132 // packet transmission in hopes of sending fewer packets
133 // (Nagle's algorithm). The default is true (no delay), meaning
134 // that data is sent as soon as possible after a Write.
135 func (c *TCPConn) SetNoDelay(noDelay bool) error {
136 if !c.ok() {
137 return syscall.EINVAL
138 }
139 return setNoDelay(c.fd, noDelay)
140 }
141
142 // DialTCP connects to the remote address raddr on the network net,
143 // which must be "tcp", "tcp4", or "tcp6". If laddr is not nil, it is used
144 // as the local address for the connection.
145 func DialTCP(net string, laddr, raddr *TCPAddr) (*TCPConn, error) {
146 switch net {
147 case "tcp", "tcp4", "tcp6":
148 default:
149 return nil, UnknownNetworkError(net)
150 }
151 if raddr == nil {
152 return nil, &OpError{"dial", net, nil, errMissingAddress}
153 }
154 return dialTCP(net, laddr, raddr, noDeadline)
155 }
156
157 func dialTCP(net string, laddr, raddr *TCPAddr, deadline time.Time) (*TCPConn, e rror) {
158 fd, err := internetSocket(net, laddr.toAddr(), raddr.toAddr(), deadline, syscall.SOCK_STREAM, 0, "dial", sockaddrToTCP)
159
160 // TCP has a rarely used mechanism called a 'simultaneous connection' in
161 // which Dial("tcp", addr1, addr2) run on the machine at addr1 can
162 // connect to a simultaneous Dial("tcp", addr2, addr1) run on the machin e
163 // at addr2, without either machine executing Listen. If laddr == nil,
164 // it means we want the kernel to pick an appropriate originating local
165 // address. Some Linux kernels cycle blindly through a fixed range of
166 // local ports, regardless of destination port. If a kernel happens to
167 // pick local port 50001 as the source for a Dial("tcp", "", "localhost: 50001"),
168 // then the Dial will succeed, having simultaneously connected to itself .
169 // This can only happen when we are letting the kernel pick a port (ladd r == nil)
170 // and when there is no listener for the destination address.
171 // It's hard to argue this is anything other than a kernel bug. If we
172 // see this happen, rather than expose the buggy effect to users, we
173 // close the fd and try again. If it happens twice more, we relent and
174 // use the result. See also:
175 // http://golang.org/issue/2690
176 // http://stackoverflow.com/questions/4949858/
177 //
178 // The opposite can also happen: if we ask the kernel to pick an appropr iate
179 // originating local address, sometimes it picks one that is already in use.
180 // So if the error is EADDRNOTAVAIL, we have to try again too, just for
181 // a different reason.
182 //
183 // The kernel socket code is no doubt enjoying watching us squirm.
184 for i := 0; i < 2 && (laddr == nil || laddr.Port == 0) && (selfConnect(f d, err) || spuriousENOTAVAIL(err)); i++ {
185 if err == nil {
186 fd.Close()
187 }
188 fd, err = internetSocket(net, laddr.toAddr(), raddr.toAddr(), de adline, syscall.SOCK_STREAM, 0, "dial", sockaddrToTCP)
189 }
190
191 if err != nil {
192 return nil, err
193 }
194 return newTCPConn(fd), nil
195 }
196
197 func selfConnect(fd *netFD, err error) bool {
198 // If the connect failed, we clearly didn't connect to ourselves.
199 if err != nil {
200 return false
201 }
202
203 // The socket constructor can return an fd with raddr nil under certain
204 // unknown conditions. The errors in the calls there to Getpeername
205 // are discarded, but we can't catch the problem there because those
206 // calls are sometimes legally erroneous with a "socket not connected".
207 // Since this code (selfConnect) is already trying to work around
208 // a problem, we make sure if this happens we recognize trouble and
209 // ask the DialTCP routine to try again.
210 // TODO: try to understand what's really going on.
211 if fd.laddr == nil || fd.raddr == nil {
212 return true
213 }
214 l := fd.laddr.(*TCPAddr)
215 r := fd.raddr.(*TCPAddr)
216 return l.Port == r.Port && l.IP.Equal(r.IP)
217 }
218
219 func spuriousENOTAVAIL(err error) bool {
220 e, ok := err.(*OpError)
221 return ok && e.Err == syscall.EADDRNOTAVAIL
222 }
223
224 // TCPListener is a TCP network listener.
225 // Clients should typically use variables of type Listener
226 // instead of assuming TCP.
227 type TCPListener struct {
228 fd *netFD
229 }
230
231 // AcceptTCP accepts the next incoming call and returns the new connection
232 // and the remote address.
233 func (l *TCPListener) AcceptTCP() (c *TCPConn, err error) {
234 if l == nil || l.fd == nil || l.fd.sysfd < 0 {
235 return nil, syscall.EINVAL
236 }
237 fd, err := l.fd.accept(sockaddrToTCP)
238 if err != nil {
239 return nil, err
240 }
241 return newTCPConn(fd), nil
242 }
243
244 // Accept implements the Accept method in the Listener interface;
245 // it waits for the next call and returns a generic Conn.
246 func (l *TCPListener) Accept() (c Conn, err error) {
247 c1, err := l.AcceptTCP()
248 if err != nil {
249 return nil, err
250 }
251 return c1, nil
252 }
253
254 // Close stops listening on the TCP address.
255 // Already Accepted connections are not closed.
256 func (l *TCPListener) Close() error {
257 if l == nil || l.fd == nil {
258 return syscall.EINVAL
259 }
260 return l.fd.Close()
261 }
262
263 // Addr returns the listener's network address, a *TCPAddr.
264 func (l *TCPListener) Addr() Addr { return l.fd.laddr }
265
266 // SetDeadline sets the deadline associated with the listener.
267 // A zero time value disables the deadline.
268 func (l *TCPListener) SetDeadline(t time.Time) error {
269 if l == nil || l.fd == nil {
270 return syscall.EINVAL
271 }
272 return setDeadline(l.fd, t)
273 }
274
275 // File returns a copy of the underlying os.File, set to blocking mode.
276 // It is the caller's responsibility to close f when finished.
277 // Closing l does not affect f, and closing f does not affect l.
278 func (l *TCPListener) File() (f *os.File, err error) { return l.fd.dup() }
279
280 // ListenTCP announces on the TCP address laddr and returns a TCP listener.
281 // Net must be "tcp", "tcp4", or "tcp6".
282 // If laddr has a port of 0, it means to listen on some available port.
283 // The caller can use l.Addr() to retrieve the chosen address.
284 func ListenTCP(net string, laddr *TCPAddr) (*TCPListener, error) {
285 switch net {
286 case "tcp", "tcp4", "tcp6":
287 default:
288 return nil, UnknownNetworkError(net)
289 }
290 if laddr == nil {
291 laddr = &TCPAddr{}
292 }
293 fd, err := internetSocket(net, laddr.toAddr(), nil, noDeadline, syscall. SOCK_STREAM, 0, "listen", sockaddrToTCP)
294 if err != nil {
295 return nil, err
296 }
297 err = syscall.Listen(fd.sysfd, listenerBacklog)
298 if err != nil {
299 closesocket(fd.sysfd)
300 return nil, &OpError{"listen", net, laddr, err}
301 }
302 l := new(TCPListener)
303 l.fd = fd
304 return l, nil
305 }
LEFTRIGHT

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